Crash barrier

ABSTRACT

A crash barrier system for forming a crash barrier including a plurality of barrier units, each barrier unit including a body having at least one crash wall, the body defining a cavity for receiving ballast; the crash wall including a series of longitudinal grooves on the outside surface thereof, each groove adapted to house a reinforcement bar; a first barrier unit is connectable to an adjacent second barrier unit by locking pins; at least one locking pin able to pass through apertures in the body of the first barrier unit and reinforcement bar(s) housed in the crash wall of the first barrier unit, and through apertures in the adjacent second barrier unit and reinforcement bar(s) housed in the crash wall of the adjacent second barrier unit so as to lock the barrier units together to form the crash barrier.

TECHNICAL FIELD

The present invention relates to a high energy absorbing crash barrier for improved road safety.

BACKGROUND

Drivers of vehicles on roads can, on occasion, lose control and cause the vehicle that they are operating to leave the road. This can be dangerous if the road is adjacent to a soft verge or other open area on which vehicles are not supposed to drive. It can also be dangerous if the area next to the road has obstacles into which the vehicle can crash. The obstacles could be e.g. telegraph poles, street lamps, trees or fences. When the vehicle crashes into an obstacle there can be damage to the vehicle, potential injury to the driver and passengers (if present) and/or damage to the obstacle, all of which is undesirable. It is even more undesirable if the obstacle includes people walking or standing next to the road. Under these circumstances, the people may be killed or seriously injured by the vehicle that is out of control.

Crash barriers are used in areas where there is the risk of injury or damage if a vehicle leaves the road. These barriers are sometimes used as a temporary measure during roadworks or during an event where people are standing next to a road, for example, as spectators.

Crash barriers can be made from moulded plastic and are typically hollow so that they are lightweight and can be easily transported to site and can be readily constructed by one or two operators. Each barrier unit can be filled with ballast such as water or sand to give it weight. The weight can act to absorb impact when a vehicle crashes into the crash barrier and can also improve the stability of the barrier by increasing the friction with the ground. The crash barrier is usually modular comprising a number of barrier units which can be connected in series to form a barrier line. The crash barrier can run along the side of the road providing a barrier between the road and a verge or, in some cases, it can run along the road to divide the road into sections.

Crash barriers can be reinforced to prevent buckling of the plastic moulded body on impact. The reinforcement can be in the form of metal bars or rods which provide increased structural integrity to the plastic body. A disadvantage of the reinforcement is that the bars themselves can become a problem if the vehicle collides with them awkwardly. The bars can increase damage to the vehicle or the bars may be dislodged on impact creating dangerous projectiles.

It is desirable to provide a crash barrier that overcomes at least some of the problems of the prior art.

The above references to the background art or background problems do not constitute an admission that the art or problems forms a part of the common general knowledge of a person of ordinary skill in the art.

SUMMARY OF THE DISCLOSURE

According to a first aspect of the invention there is provided a crash barrier comprising a plurality of barrier units, each barrier unit comprising:

a body having at least one crash wall, the body defining a cavity for receiving ballast;

the crash wall comprising a series of longitudinal grooves on the outside surface thereof, each groove adapted to house a reinforcement bar;

wherein a first barrier unit is connectable to an adjacent second barrier unit by locking pins; at least one of the locking pins able to pass through apertures in the body of the first barrier unit and any reinforcement bars housed in the crash wall of the first barrier unit, and through apertures in the adjacent second barrier unit and any reinforcement bars housed in the crash wall of the adjacent second barrier unit so as to lock the barrier units together to form the crash barrier.

The locking pin and the apertures in barrier units and bars together provide a locking arrangement. There can be multiple barrier units connected to one another by the locking arrangement to form the crash barrier.

The locking arrangement provides interconnection of the reinforcement bars along the length of the crash barrier (sometimes referred to as the barrier line). The interconnection of the bars provides continuous reinforcement along the barrier line. When a vehicle impacts the crash barrier, the impact is distributed along the barrier line through the joined reinforcement bars. Vehicular impact is thought to be transferred as a longitudinal tensile force along the crash barrier line.

The reinforcement bars are also interconnected with the bodies of the barrier units. This means that impact force is also distributed into each of the barrier unit bodies; some of the impact energy possibly being absorbed and dissipated by the ballast therein.

When a vehicle hits the crash barrier, the interconnection of the reinforcement bars with each other and with the barrier unit bodies can prevent or significantly reduce the likelihood of dislodgement of the bars. It is a requirement by International Standards that reinforcement bars are not dislodged on impact, so in preferred embodiments, there is no dislodgement of the bars on impact. This means it is less likely that the bars will penetrate the impacting vehicle or be dislodged and become projectiles

The crash barrier can provide a high energy absorbing road safety barrier which can reduce the severity of crashes. It can also minimise the dynamic displacement of the crash barrier under different crash velocities, thereby potentially protecting lives, mitigating injury, and reducing damage to road side objects. By “dynamic displacement”, it is meant movement of the crash barrier from its starting position before impact.

Each barrier unit is a container having outer walls defining an interior cavity. Each barrier unit has a first end and a second end. A plurality of connecting lugs can be disposed at the first and second ends to allow for connection of adjacent barrier units. A recess can be formed between each connecting lug. In order to form the crash barrier, connecting lugs from a first end of a first barrier unit are received into the recesses of the second end of the adjacent second barrier unit. Multiple barrier units mated together in this way form the crash barrier.

There can be apertures in each of the connecting lugs. The apertures in the connecting lugs can overlap when the respective ends of barrier units are mated.

The crash wall is the wall of the barrier unit that the vehicle will collide with. By “crash wall” it is meant the wall intended for impact by a vehicle. Each crash wall can be reinforced with reinforcement bars. When the crash barrier runs along the side of a roadway, only one side of each barrier unit may be available as a crash wall. When the crash barrier run along the roadway with vehicles on either side, both sides of the barrier units are available as crash walls. Two opposing crash walls provide structural integrity to the crash barrier once formed and thus optimal impact absorption. The crash walls are joined by the first and second ends of the barrier units.

The barrier unit can be cuboidal. The barrier unit can have a substantially rectangular cuboidal shape. It should be understood that other shapes that are able to join end to end to form a barrier line are within the scope of the invention e.g. rhomboids. The barrier units can have a wider base to provide stability.

The length of the crash barrier will depend on the number of barrier units used. The length can be determined according to the area that the crash barrier is intended to protect. This can be referred to as the Length of Need (LON). The crash wall(s) extending between the first and second ends can be of any length. The crash wall can be up to about 3 meters in length, such as between 1 and 3 meters in length. The crash wall may be 1, 2, 2.5 or 3 meters in length. If ten barrier units of about 2.5 meters are used, the crash barrier will be about 25 meters in length.

The width of each barrier unit (i.e. the distance between the first crash wall and the opposing second crash wall) can depend upon the length of the crash wall; e.g. the longer the crash wall, the wider the barrier in order to allow the barrier unit to be free standing. Each barrier unit can be up to about or at least 0.3 meters in width. The barrier unit can be at least 0.4, 0.5, 0.6, 0.7 or 0.8 meters in width.

The barrier unit can be made of plastic. The plastic can be polyurethane or polyethylene. The thickness of the barrier walls can be at least 3, 5, 8 or 10 mm. The skilled person will appreciate which materials and which thicknesses of materials are suitable for use in crash barrier units. The barrier unit can be coloured to provide high visibility. For example, the barrier unit can be orange.

Each barrier unit can be filled with ballast. The ballast provides weight to each barrier unit. The ballast can be chosen from e.g. sand and water. The barrier unit can be filled with ballast to at least about 80% of capacity such as between 80 and 95% of capacity. The barrier unit can be filled to at least 10, 20, 25, 40 or 50% capacity. The barrier unit can be completely filled, i.e. to 100% of capacity. The barrier unit can be filled until sit weighs at least about 300, 500, 100 or 1,500 kg. Water is the preferred ballast because it is easy to remove when the crash barrier is required to be disassembled. In order to add and remove water, there can be an opening in the body of the barrier unit. The opening can act as a drain which can be plugged when the barrier is in use.

The barrier unit does not need to have a top wall because ballast can be held without a top wall. However, a top wall in the barrier unit is preferred, because it provides structural integrity to the barrier unit. The top wall of the barrier unit can be reinforced to provide further structural integrity to the barrier unit. The reinforcement in the top wall can be grooves in the moulded plastic of the top wall. The reinforcement in the top wall of the barrier unit can be an elongate metal strip embedded in the top wall.

The connecting lugs can extend across the entire width of the first and second ends of the barrier unit. Alternatively, some of all of the connecting lugs can extend across a part of the first and second ends of the barrier unit. In this embodiment, the connecting lugs are offset with respect to one another. The connecting lugs at the first and second ends of the barrier unit can have rounded, triangular or square profiles. A squared profile is preferred because it reduces lateral movement of the barrier units around the connection point between barrier units. There can be 2, 3, 4, 5 or 6 connection lugs per end of each unit. There can be three connection lugs at each end of the barrier unit. Three connection lugs can result in 2 recesses (1 recess between each pair of lugs).

Each barrier unit can be formed so that it can be used either way up and still mate with an adjacent unit. This provides for easier construction, because the operator need not concern himself or herself with the orientation of each barrier unit as it is provided for use.

The crash wall of each barrier unit is provided with one or more longitudinal grooves (sometimes referred to as just “grooves”). The grooves run the entire length of the crash wall. The grooves can be substantially parallel with the roadway on which the unit sits. The grooves are for housing a reinforcement bar. The reinforcement bar can be made of any material which is strong and provides crash impact resistance. The reinforcement bar provides structural integrity to the plastic body of the barrier unit. The reinforcement bar can be metal. The reinforcement bar can be steel.

In use, each reinforcement bar is housed on the outside surface of the barrier unit. The advantage of having the reinforcement bars on the outside of the barrier unit is that the material of the bar does not contact with the ballast in the cavity. If the bar is metal and the ballast is water, the water ballast could rust the metal of the bar.

The reinforcement bar can be a snug fit into the longitudinal groove in the crash wall so it is substantially retained therein by frictional force. The reinforcement bar can be housed into the groove before the ballast is added to the cavity. The reinforcement bar can then be compressed and held in the groove by the force of the ballast inside the barrier unit and remain in the groove especially during and following an impact.

There can be a plurality of longitudinal grooves arranged in series in each crash wall. Each of the grooves can run substantially parallel with one another. There can be at least 1, 2, 3, 4 or 5 longitudinal grooves in series each for housing a reinforcement bar. In one embodiment, there are 3 rows of grooves on each side of the crash barrier.

In use, not all of the grooves need to have a reinforcement bar housed therein. Some grooves may be empty in use. However, the more grooves that are reinforced the less deformation of the body of the barrier unit on impact.

It is desirable for the crash barrier to absorb vehicular impact, but also to redirect the vehicle upon impact. It has been observed that the centre of gravity of the vehicle as well as the role of front tyres play an important role in the redirection of the vehicle. The height of each groove in the crash wall (with respect to the roadway) can be determined so as to provide the optimal vehicular impact absorption. At least one of the grooves in the crash wall can be at least about 500 mm from the roadway on which the barrier unit sits. A height of 500 mm has been found to correspond to provide optimal impact absorption. The rows of grooves can be up to about 300, 400, 500, 600 and/or 700 mm in height from the roadway. The rows can be spaced up to about 100, 200, 300 or 400 mm apart. In one embodiment, the rows are at heights of about 300, 500 and 700 mm, In this embodiment the rows are about 200 mm apart.

The lowermost reinforcement bar can be housed at about 300 mm from the road which may assist to reduce under-ride or override of the impacting vehicle. There can be grooves in the body of the barrier unit to help increase friction with the road on which the barrier sits. This may assist in minimising slip of the barrier unit under wet conditions.

The number of rows of reinforcement bars in the crash wall can be chosen to correspond to the maximum speed of the vehicles on the road on which the crash barrier will be used. The crash barrier can be reinforced to withstand vehicles travelling at speeds in the range of from about 50 km/h to about 100 km/h Most roadworks are undertaken on roads with a reduced speed limit. The road on which the barrier unit sits may be rated for 10, 20, 3) or 40 km/h. Nevertheless, vehicles may be travelling at higher speeds. If it is expected that vehicles will be travelling at most at 50 km/h, there may be two rows of reinforcement bars to provide crash impact. A crash barrier for a road having vehicles travelling at a speed of at most 50 km/h may have a single row of reinforcement at about 500 mm from the ground. If the road may have vehicles travelling at a speed of 70 km/h, there could be two rows of reinforcement at about 300 and about 500 mm from the ground. If the road may have vehicles travelling at a speed of 100 km/h, there may be three rows of reinforcement bars at about 300, 500 and 700 mm to improve the stiffness of the barrier and to provide crash impact resistance.

The longitudinal grooves in the outside surface of the crash wall can be of any cross-sectional shape. If there is more than one row of grooves in a crash wall, each can be a different cross-sectional shape, or they can all be the same shape. The cross-section of the longitudinal grooves can be shallow and curved. The cross-sectional shape of the grooves can be substantially square, rectangular or triangular shaped.

Each reinforcement bar is elongate. The reinforcement bar chosen for use can be hollow. The reinforcement bar can be solid. The cross-sectional shape of the reinforcement bar can correspond to the shape of the longitudinal groove into which is will be housed. The cross-sectional shape of the reinforcement bar can be square, triangular, circular, oval or rectangular. Compared to a circular section, bars with rectangular sections will offer added advantages by increasing the confining pressure inside the filled barrier units more quickly and effectively. When compared with the square sections, the rectangular sections will optimise the performance of the crash barrier due to higher inertia about the major axis. Consequently, rectangular sections of bar are most preferred even though these bars are more susceptible to corrosion compared to the circular sections due to residual stress accumulated at corners of the bars.

Each reinforcement bar is slotted into the longitudinal groove when the barrier unit is in use. The reinforcement bars have an aperture at each peripheral end. The peripheral end of each reinforcement bar can have a reduced thickness to allow for overlapping of the bars with one another. When the reinforcement bars are in the longitudinal grooves in the crash wall, the apertures in the reinforcement bars line up with the apertures in the connecting lugs of the barrier unit bodies, as described above.

The apertures of the one or more reinforcement bars and the connecting lugs of the barrier units line up when the barrier units are mated to form a passageway through which a single locking pin can pass. The locking pin therefore passes through the body of a first barrier unit and the body of a second adjacent barrier unit and the apertures in the reinforcement bars. This means that a single locking pin can be used to join and interconnect barrier unit bodies and reinforcement bars.

The apertures in the mated connecting lugs line up with apertures in the reinforcement bars in the crash wall. This means that when there are two crash walls, there are apertures on both sides of the barrier unit body so that a passageway can form for the reinforcement bars on the first side in the crash wall and a passageway can form for the reinforcement bars on the second, opposing side in the opposing crash wall. The apertures line up on one side to form a first passageway for a first locking pin; and line up on the second side to form a second passageway for a second locking pin. There are two locking pins at every connection point between barrier units. When viewed from above, each barrier unit has a locking pin positioned towards each corner of the structure. Thus, for a rectangular cuboidal barrier unit in a crash barrier line, when viewed from above, there are four locking pins; one in each corner.

The locking pin is elongate and can have an integrated head and body. The locking pin can made from a strong and resilient material that substantially resists bending or buckling on impact. The locking pin can be made from steel. The locking pin can have a diameter that provides it with sufficient strength to withstand impact without substantially bending or buckling.

The diameter of the locking pin can be smaller than the diameter of the passageway formed by the apertures. The diameter of the passageway can be up to about 10, 20, 30 or 40 mm larger than the diameter of the locking pin body. This allows some movement of the barrier units around the locking pin.

The head of the locking pin should be larger than at least the topmost aperture in the barrier unit body to ensure that the head cannot pass through the aperture. In order to prevent or at least reduce possible engagement of the impacting vehicle with the head of the locking pin, the head can be embedded inside a correspondingly shaped socket in the body of the barrier unit. By embedding the head of the pin in a socket, the chance that the head will shear off the body is also reduced. The socket can be slightly larger than the head of the pin to allow the operators to get his fingers around the head of the pin to remove it.

The locking pin can be spaced at a distance of at least about 10, 15, 25 or 35 mm from the crash wall to provide sufficient plastic body material between the pin and any vehicle that impacts with the crash wall. The locking pin can be spaced at a distance of up to about 50, 75, 100, 150 or 200 mm from the crash wall. The distance from the crash wall can be measured from the surface of the crash wall and the longitudinal central axis of the locking pin.

The locking pin can be simply passed through the apertures and held in place by gravity. When the locking pin needs to be removed, it can simply be pulled upwards. This means that the crash barrier can be readily disassembled without the need for special tools. It also means that if there is vehicular impact and emergency services require access from the other side of the barrier, it can be readily disassembled.

The crash barrier of the present invention can be slightly curved along the barrier line. Over about 20, 25 or 30 meters, a bend of at least about 2, 3, 4 or 5 degrees in the crash barrier as measured from one end of the barrier can be obtained. The bend can be obtained by adjusting the barrier units with respect to one another and is possible due to small gaps between the barrier units and because the locking pin(s) have room to move in the passageway(s). The bending in the barrier line can mean that the crash barrier is most useful on road corners (or bends) rated for speeds above about 25 30, 45, 50 or 55 km/h. The barrier can also be used where there are vehicles that may be travelling at speeds up to about 80, 90 or 100 km/h.

The lack of inherent bend in the crash barrier means that there is reduced dynamic displacement of the crash barrier on impact. This is an advantage if the barrier is to protect obstacles which are located near to the barrier (i.e. within a few meters). When a vehicle impacts with the crash barrier, the distance that the crash barrier moves from a given starting point (dynamic displacement (d)) is up to about 3 meters, such as in the range between 1 and 3 meters. The dynamic displacement of the barrier can be at most about 0.5, 1, 2 or 3 meters. The dynamic displacement is measured from the far face of the crash barrier and is measured at the most distant point from the starting position. The starting point is the horizontal mid-line of the crash barrier at rest (i.e. before impact).

The crash barrier is able to redirect the vehicle along the barrier line. By redirect, it is meant that the vehicle is guided along the barrier line and does not deflect or otherwise rebound away from the barrier such that it could become an obstacle for oncoming traffic. In embodiments, the crash barrier of the invention can satisfy the requirements for redirection given in European Standards: EN 1317 while fulfilling other requirements given in the Manual for Assessing Safety Hardware (MASH) (2009).

In another aspect there is provided a crash barrier when formed in accordance with the system of the first aspect of the invention. In yet another aspect there is provided a barrier unit as described in the system according to the first aspect of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described with reference to the following drawings which are exemplary only and in which:

FIG. 1(a) is a side plan view of a first barrier unit mated with a second barrier unit in accordance with a first embodiment of the invention;

FIG. 1(b) is an end view of the barrier units of FIG. 1(a); FIG. 1(c) is a top view of the barrier units of FIG. 1(a);

FIG. 1(d) is a perspective view of the barrier units of FIG. 1(a);

FIG. 2 is a side plan view of three barrier units joined in series to form a crash barrier according to an embodiment of the invention;

FIG. 3 is a perspective view of the barrier units of FIG. 1;

FIG. 4 is a perspective view of a first and second barrier unit in accordance with a second embodiment of the invention;

FIG. 5 is a top view of a vehicle about to crash in a crash barrier according to an embodiment of the invention;

FIG. 6(a) is a perspective view of FIG. 4 in which there are two rows of reinforcement shown in the crash barrier;

FIG. 6(b) a perspective view of FIG. 4 in which there are three rows of reinforcement shown in the crash barrier;

FIG. 7 is a top view close up of a vehicular impact with a crash barrier according to an embodiment of the invention;

FIG. 8 is a graph showing displacement of the barrier at various impact speeds (a) 50 km/h, (b) 70 km/h and (c) 100 km/h.

FIG. 9 is a schematic showing vehicular impact in series from (a) to (d);

FIG. 10(a) is a graph showing lateral deflection (in mm) perpendicular to the crash barrier at 70 km/h

FIG. 10(b) is a graph showing longitudinal displacement (in mm) along the crash barrier at under 70 km/h

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

FIG. 1(a) is a side view of a first barrier unit 10 connected to a second adjacent barrier unit 10 according to a first embodiment of the invention. The first barrier unit body (left) is shown as transparent for illustrative purposes only. Each barrier unit 10 has a first end 12; and a second end 13. FIG. 1(b) is a plan view of the first end 12 of barrier unit 10.

The first and second ends of each barrier unit have three connecting lugs 14. The connecting lugs 14 extend outwardly from the first and second ends and can comprise hollow portions as shown. The connecting lugs 14 can have ribs and channels to provide them with reinforcement. There are two recesses 16 formed between the lugs 14. When the connecting lugs 14 and recesses 16 of barrier units 10 are mated, the barrier units fit snugly together as shown in FIG. 1(a). The complementary fit of the ends of units 10 is shown at connection 18.

In use, the first barrier unit 10 is mated with a second barrier unit 10 by pushing the free standing barrier units together. A number of barrier units can be mated together to form the crash barrier. The crash barrier can be of any desired length, which will depend upon the length of area designated for protection. In one embodiment, in which each crash barrier unit is about 2.5 meters in length, there are 20 barrier units in series resulting in a crash barrier that is about 50 meters in length. Each barrier unit can be about 50 cm in width.

Top wall 32 of each barrier unit can comprise moulded grooves to provide additional structural integrity to the unit. The grooves can be seen in the plan view of top wall 32 and can also be seen clearly in FIG. 3.

The barrier units in FIG. 1 each have three longitudinal grooves 20 in their crash wall 22. Reinforcement bars 24 are shown housed in the grooves. The reinforcement bars 24 can be inserted into the grooves once the barrier units 10 are mated in a line. The reinforcement bars are pushed by the operator from one peripheral end until they each fit snugly into the corresponding groove. The reinforcement bars 24 are added along the crash barrier line to form a continuous line of reinforcement.

The heights of the reinforcement bars 24 with respect to the roadway on which the barrier unit sits are selected so as to provide optimal absorption of energy upon impact. In FIG. 1, the bars are shown at heights 300, 500 and 700 mm.

The peripheral end of each reinforcement bar 24 is adapted to overlap with the end of another reinforcement bar 24. This is shown in e.g. FIG. 1 as the thickness of reinforcement bar 24 being reduced at each end to allow for the overlap. The overlap occurs at the connection 18 between each barrier unit.

FIG. 1(d) is a perspective view of the barrier units of FIG. 1(a). There are apertures 26 formed in the connecting lugs 14. There are also apertures 28 in each of the ends of reinforcement bars 24. When the barrier units are mated, the apertures line up to form a passageway. At each connection point 18 between barrier units 10, there is a first passageway formed including apertures in the reinforcement bars 24 in the first crash wall 22 of the barrier unit 10. There is a second passageway formed including apertures in the second, opposing crash wall 22′ of the barrier unit 10.

Each passageway is able to receive a locking pin 30. The locking pin connects the adjacent barrier units 10 a and 10 b. Locking pins 30 can be seen in position in FIG. 2. FIG. 3 is a perspective view of barrier units 10 a and 10 b when moved apart from one another. For illustrative purposes only, locking pin 30 is shown in the passageway formed by apertures 26 and 28. It can be seen that at each connection point there are two locking pins one towards each crash wall 22 and 22′. When viewed from above (FIG. 1(c)), it can be seen that there are four locking pins per barrier unit 10, although it should be understood that two of the four locking pins are shared by an adjacent barrier unit 10.

FIG. 4 perspective view of a second embodiment of a barrier unit of the invention. First barrier unit 110 is shown adjacent to a second barrier unit 110. The difference in the second embodiment as compared to the first embodiment is in the configuration of connecting lugs 116. As can be seen, at first end 112 there are three connecting lugs 114 offset from one another. Each connecting lug 114 does not extend across the full width (w) of the barrier unit 110 and instead extends only half way across the width. A recess 116 is formed between top and bottom lugs. Recesses 116′ and 116″ are also present above and below a centrally positioned lug 114′.

When the barriers 110 are mated, apertures in the respective lugs line up to form a passageway in the same way as in the first embodiment of the invention. Reinforcement bars are not shown in position in this embodiment,

Once the reinforcement bars 24 and locking pins are in place the water ballast can be added to each barrier unit. The advantage of adding the ballast after the reinforcement bars 24 and locking pins are inserted, is that the pressure exerted by the ballast can act to squash and retain the reinforcement bar in the respective grooves and squash and retain the locking pins in the passageways. If the bars 24 and pins 30 are added after the addition of the ballast, it can be difficult to insert them and the heavy units weighted with ballast can be difficult to move.

The water ballast is added into the top of each barrier unit through an opening (not shown). The water can be delivered by a pipe. In this embodiment, water is added until each barrier unit is about 25% filled. The barrier unit weighs about 200 kg following the addition of ballast. Once the water ballast has been added, the opening can be plugged to reduce evaporation of the ballast in use.

The head 33 of each of the locking pins 30 is recessed into top wall 32 (not shown). This can prevent shear of the head of the pin on vehicular impact.

FIG. 5 shows fifteen barrier units joined end to end to form crash barrier 100. There are continuous lines of reinforcement bars 24 in the crash barrier 100. These lines of reinforcement can act to absorb impact from vehicle 34. Vehicle 34 is about to crash into the crash walls of the crash barrier 100. A closer view of the impending impact can be seen in FIG. 6 where vehicle 34 is shown with respect to the height of the reinforcement bars 24. In FIG. 6(a), the vehicle 34 is shown about to crash into a barrier with two rows of reinforcement at 300 mm and 500 mm. In FIG. 6(b) the vehicle 34 is shown about to crash into a barrier with three rows of reinforcement at 300, 500 and 700 mm. As vehicle 34 impacts with the crash barrier 100, impact force is distributed along the barrier line.

EXAMPLES

Embodiments of the invention will now be described with reference to the following examples.

Example 1

Numerical simulations of an impact with the crash barrier of this project were conducted a vehicle model including a Chevy Silverado (2007) pickup truck shown in e.g. FIG. 5, The truck has a mass of 2270 kg to comply with the proposed MASH-08 test level 3-11.

A crash barrier in accordance with an embodiment of the invention was simulated to be 30 m in length. According to the MASH-08 test level 3-11 requirements, the crash barrier was kept straight and level. The critical impact point was selected to test the ability of the barrier to contain and redirect the test vehicle in the recommended manner within the Length Of Need (LON). The critical impact point was close to the mid span of the barrier line, located 14 m away from the downstream end of the barrier line.

It was observed that the maximum dynamic deflection occurs at the far face of the impacted point. Maximum displacement under 100 km/h, 70 km/h and 50 km/h speeds were 2.2 m, 0.8 m and 0.5 m respectively. FIG. 8 is a graph showing the lateral (perpendicular) displacements during the 100 km/h, 70 km/h and 50 km/h impacts respectively along with representative screen shots (FIGS. 8(a) to (c)) from LS-DYNA.

Risk of occupant injury during impact with barriers depends, to a large extent on the crashworthiness of the impacting vehicle. The crashworthiness depends on the design of occupant compartment. However, the variability of vehicular crashworthiness has been removed from the safety feature evaluation. Thus, occupant risk is appraised according to gross vehicular accelerations because they are primarily function of the safety feature design and external structural design of the test vehicle (MASH 2009).

It was observed that there are no detached elements, fragments, or fractured components of the impacting vehicle penetrating or potentially penetrating the passenger compartment. Also there are no detached elements that risk other traffic, pedestrians or personnel in the work zone. Additionally, there are no detached elements, fragments or other debris resulting from the impact which block the driver's vision or otherwise cause the driver to lose control of the vehicle. Moreover, there is no rollover during and after the impact and maximum roll and pitch angles do not exceed 75 degrees.

Deformation of, or intrusion into, the occupant compartment does not exceed the limits set forth in MASH 2009 as shown in Table 1.

TABLE 1 Maximum allowable deformation criteria Allowable deformation Components (mm) Roof 102 Windshield-no tear of plastic liner  76 Window-no shattering No shattering Wheel/foot well and toe pan areas 229 Side front panel 305 Front side door area (above seat) 229 Front side door area (below seat) 305 Floor pan and transmission tunnel 305 area

The occupant was allowed to “flail” 0.6 meters in the longitudinal direction (parallel to the typical direction of vehicle travel) and 0.3 meters in the lateral direction prior to impacting the vehicle interior.

Measured vehicle kinematics are used to compute the difference in velocity between the occupant and occupant compartment at the instant the occupant has reached either 0.3 meter laterally or 0.6 meter longitudinally.

For ease of computations, the vehicle yaw and pitch motions were ignored, all motion is assumed to be in the horizontal plane, and the lateral and longitudinal motions are assumed to be independent.

At the instant of occupant impact, the largest difference in velocity (lateral and longitudinal directions are handled independently) is termed the occupant impact velocity (VI). Once the impact with the interior occurs, the occupant is assumed to remain in contact with the interior and be subjected to any subsequent accelerations of the vehicle. The maximum 10 ms moving average of the accelerations subsequent to the occupant impact with the interior is termed the occupant ridedown acceleration.

It is observed that the resultant Impact Velocity and Ridedown Acceleration fall within the required limits set by MASH (2009).

Example 2

FIG. 7 is a top view of the vehicle 34 following impact with the crash barrier 100. The dynamic displacement of the barrier can be seen by arrow “d”. For a crash barrier that has a total barrier length of 30 meters, the middle (or mid-span) is 15 meters. In an embodiment, the maximum deformation of the crash barrier at 14 meters from the downstream end is about 2.2 meters. However, when the vehicle hits close to the one of the ends of the crash barrier (not at mid span) the displacement (d) will increase and vehicle may not be properly redirected. There is an optimum length from the end of the crash barrier where the barrier can fulfil its intended task upon impact which is the Point of Need (PON).

The optimum length of a crash barrier (or leading PON) in this example is 8 m for impacts at 100 km/h (with 2270 kg vehicle). This can be compared with barriers manufactured and marked with the Trade Mark Triton® which require a length of 40 m (100 km/h—with 2000 kg vehicle) to provide the same protection as the barrier of an embodiment of the present. This can also be compared with barriers manufactured and marked with the Trade Mark ArmorZone® which require a length of 14 m (70 km/h—with 2000 kg vehicle) to provide the same protection as the barrier of an embodiment of the present.

Example 3

A redirected impact, for a plastic water filled crash barrier, is shown in FIG. 9. In FIG. 9 (a) a vehicle 234 is shown about to crash into barrier 200. FIGS. 9 (b), (c) and (d) show the result of the impact. In FIG. 9(d) the redirection of the vehicle is shown by the Exit Box. The ‘Exit Box’ is a requirement in Standard EN 1317. A redirection within the limit marked by “A” means the barrier complies with the Standard. A redirection that exceed limit “A” is a barrier which fails to comply with the Standard. Simulations involving the barrier of embodiments of the present invention result in compliance with Standard EN 1317.

In embodiments, the crash barrier can redirect a 2270 kg pickup truck even under 100 km/h impact. Moreover, as far as the lateral deformation and Length of Need (LON) are concerned, they are the minimum compared to the recorded lateral deformations and LON of the deformable barriers existing in the world.

Example 4

A simulation was run in accordance with Example 1. The results are shown in FIG. 10. FIG. 10(a) is a graph showing lateral deflection (in mm) perpendicular to the crash barrier at 100 km/h. FIG. 10(b) is a graph showing longitudinal displacement (in mm) along the crash barrier at 100 km/h.

The lateral displacement under 50 km/h (500 mm) (not shown) is approximately half of that under 70 km/h (1000 mm) whilst being a quarter of the lateral displacement (2000 mm) under 100 km/h as shown in FIG. 8(a). This implies that the displacements follow the ratio of kinetic energies (1:2:4).

Whilst a number of specific embodiments have been described, it should be appreciated that the device may be embodied in many other forms.

In the claims which follow, and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word “comprise” and variations such as “comprises” or “comprising” are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the device as disclosed herein. 

1. A crash barrier system for forming a crash barrier comprising a plurality of barrier units, each barrier unit comprising: a body having at least one crash wall, the body defining a cavity for receiving ballast; the crash wall comprising a series of longitudinal grooves on the outside surface thereof, each groove adapted to house a reinforcement bar; wherein a first barrier unit is connectable to an adjacent second barrier unit by locking pins; at least one locking pin able to pass through apertures in the body of the first barrier unit and reinforcement bar(s) housed in the crash wall of the first barrier unit, and through apertures in the adjacent second barrier unit and reinforcement bar(s) housed in the crash wall of the adjacent second barrier unit so as to lock the barrier units together to form the crash barrier.
 2. A crash barrier system according to claim 1, wherein the body of each barrier unit has a first end and a second end, and wherein the first and second ends each comprise connecting lugs with recesses formed therebetween so that, in use, the connecting lugs of the first end of the first barrier unit can be mated into complementary recesses in the second end of the second barrier unit.
 3. A crash barrier system according to claim 2, wherein the connecting lugs have apertures therein and wherein: apertures in the mated connecting lugs line up with apertures in the reinforcement bar(s) housed in the first crash walls of the mated barrier units to form a first passageway for a first locking pin; and wherein apertures in the mated connecting lugs line up with apertures in any reinforcement bars housed in the second, opposing crash walls of the mated barrier units to form a second passageway for a second locking pin.
 4. A crash barrier system according to claim 1, wherein the locking pin has a head and a body, and the head is received into a socket or recess formed in the body of the barrier unit.
 5. A crash barrier system according to claim 1, wherein the longitudinal grooves in the at least one crash wall of each barrier unit are at a height of up to about 300 and/or up to about 500 and/or up to about 700 mm from a roadway on which the barrier unit is placed.
 6. A crash barrier system according to claim 1, wherein the longitudinal grooves are spaced from about 100 to about 300 mm apart.
 7. A crash barrier system according to claim 1, wherein at least one of the reinforcement bars is formed from steel.
 8. A crash barrier system according to claim 1, wherein at least one of the reinforcement bars is hollow.
 9. A crash barrier system according to claim 1, wherein at least one of the reinforcement bars has a rectangular cross-section.
 10. A crash barrier comprising a plurality of barrier units, each barrier unit comprising: a body having at least one crash wall, the body filled with ballast; the crash wall comprising a series of longitudinal grooves on the outside surface thereof, at least one groove in the series housing a reinforcement bar; wherein a first barrier unit in the crash barrier is connected to an adjacent second barrier unit in the crash barrier by a locking pin; the locking pin passing through apertures in the body of the first barrier unit and at least one reinforcement bar housed in the crash wall of the first barrier unit, and through apertures in the adjacent second barrier unit and at least one reinforcement bar housed in the crash wall of the adjacent second barrier unit so as to lock the barrier units together to form the crash barrier.
 11. A barrier unit for forming a crash barrier comprising a plurality of the barrier units joined together, the barrier unit comprising: a body having at least one crash wall, the body defining a cavity for receiving ballast; the crash wall comprising a series of longitudinal grooves on the outside surface thereof, each groove adapted to house a reinforcement bar; wherein the barrier unit is connectable to an adjacent barrier unit by locking pins; at least one locking pin able to pass through apertures in the body of the barrier unit and reinforcement bar(s) housed in the crash wall of the barrier unit, and through apertures in the adjacent barrier unit and reinforcement bar(s) housed in the crash wall of the adjacent barrier unit so as to lock the barrier units together to form the crash barrier.
 12. (canceled) 